This invention pertains to a transfer tube and seal structure for use in hydraulic devices and, more particularly, to use of such structure in a hydraulic unit for connecting flow passages between a housing of a pump or motor and a floating valve plate which conducts flow to and from a cylinder block movably mounting a plurality of pistons.
The use of transfer tubes in hydraulic units is generally known in the art, as shown in U.S. Pat. Nos. 3,059,432, 3,136,263, 2,273,468, and 3,808,950. Several of these patents show the use of seal rings for sealing the transfer tube to the walls of the flow passages which are connected by the transfer tubes. The prior art has not shown a transfer tube and seal ring structure particularly suitable for use with a floating valve plate which adjusts its position during operation and which requires minimal force in assembly and provides less resistance to movement of the valve plate because of less outward force imposed by the seal rings.